Tru Power Engine Kit. 4-Cylinder Gas, 113 CID, 3 inch Standard Bore, 3-1/8 inch Overbore Supplied. Flat-Head Standard Compression Piston, Cylinder Sleeve 3-5/16 inch O.D. at Seal, 4-25/32 inch Valve Length. Engine Overhaul Kit. Contains sleeves & sleeve seals, pistons & rings, pins & retainers, pin bushings, complete gasket set with crankshaft seals, intake & exhaust valves, springs, guides, valve keys, .002 inch rod and main bearings . For A Series, B Series, BN Series, Super A Series (prior to S/N 255417), Super AV Series (prior to S/N 255417).